Generally, bridges are structures that are constructed in various types and various shapes considering the types of objects to be supported by the bridges and to uses of the objects. Further, the bridges function to safely keep up the functions of passageways or facilities supported by the bridges, so the bridges must have a sufficient degree of strength and endurance.
As shown in FIG. 1, a conventional upper structure for bridges includes a coping 2 that is placed on the top end of a pier 1, girders 4 that are held on the coping 2 with the interposition of respective bridge bearings 3, and a deck (not shown) that is laid on the girders 4 and forms a passageway for vehicles.
As shown in FIG. 2, the girders 4, which are placed to be adjacent to each other in a longitudinal direction of a bridge, are arranged continuously on the pier 1 and on the coping 2. Here, the continuous arrangement of the girders may be accomplished in a prestressed state in which a prestressed member (prestressed steel strand) 5 is installed.